Group Scheduling (GS) allows for a hierarchy of groups to be created that represents
how an application should be scheduled. Groups can contain tasks or groups and
both tasks and groups can belong to multiple groups. Each group is associated
with an scheduling decision function that controls the members of the group.

The Computation Component Set Manager (CCSM) is a sub-system
supporting the tracking of set membership, which is useful for a wide
range of purposes. The most relevant in this context is that, since
each set can have a name, CCSM is useful in associating names with
threads for purposes of GS hierarchy specification. The CCSM can be
used to track other components as well, and for reasons beyond its use
with GS, but that is beyond the scope of this dscussion.

The motivation for a name space of threads is grounded in the fact
that specifying the instrumenation configuration for an experiment or
specifying the GS hierarchy that will control execution is
considerably easier if names can be used for application threads that
are invariant across application execution instances.